Another aspect I wanted to look at was if whether or not a prospect visited a team during Draft season influenced if that team eventually selected said player. To do this, I found Walter Football's team visit list very helpful and tabulated the results for 2013. I hope to do the same for previous years as well to improve on the accuracy.
Here's a breakdown of what teams brought in what positions (and was reported and collected by Walter Football) for visits or were confirmed to have spoken with them at gatherings. Again this is just what was reported so that's likely the reason for the disparities in numbers, most teams probably bring in about the same number each year.
The columns were conditionally formatted, with the dark green values indicating that team worked out that position more than other teams worked out the position in the same column, same with the grand totals at the end:
There's some pretty clear indicators in there. Some I can think of: New England and Philadelphia like to do their homework, Atlanta scouted a bunch of DB (and picked one 1st round), Buffalo scouted a bunch of QB (and surprise picked one 1st round) and DB and DL were met with by almost every team.
Here's whether or not each team's 1st round pick visited or not (for the record, 61% or 19 of the 31 known prospects did):
One guess as to why more teams didn't bring as many prospects in that they ended up selecting towards the end of the round could be that those team's picked more from the "best player available" methodology and ended up with people they didn't initially believe they would have the opportunity to draft.